1. Field of Invention
The invention relates generally to content distribution networks and content control. In one exemplary aspect, the invention relates to the use of identification and security (e.g., cryptographic) functions to make an association between content downloaded by a network device, and the network to which the device is coupled.
2. Description of Related Technology
Recently, Digital Video Recorders (DVRs) have become a popular consumer product. A DVR allows personalized control over a multimedia program in the form of “trick modes” (e.g. pause, rewind, fast forward) while watching it as well as providing “time shifting” capabilities by recording the program to local storage. Time shifting allows the user to watch a program at the time they want, not just when broadcast. This application is also commonly referred to as Personalized Video Recorder (PVR).
Early implementations of DVR used analog video capture and compression techniques to convert multimedia content into a digital format (e.g., MPEG bitstream) for storage on a local storage device. Recently, content distribution network operators such as cable MSO's and digital television broadcast satellite operators have begun offering DVR functionality in the consumer premises equipment (CPE) used to receive and decode digital multimedia programming.
Inclusion of the DVR functionality with a digital set-top box makes the intermediate stage of conversion of multimedia program to/from analog format unnecessary. Since content is made available over the network in digital format, an exact copy of the content can be stored locally (e.g., on a hard drive within the CPE). While this approach improves the fidelity of content for the end user, it raises copyright concerns for content owners/developers and network operators. For example, network operators have desired a solution such that valuable multi-media content downloaded from their network and stored on a CPE is somehow intrinsically tied to that network, so that it cannot be played back if the CPE is disconnected from the originating network or the content is otherwise transferred to another device.
A variety of approaches to content distribution, storage and copyright protection/digital rights management are present in the prior art. For example, U.S. Pat. No. 6,240,401 to Oren, et al. issued May 29, 2001 entitled “System and method for movie transaction processing”, U.S. Pat. No. 6,851,063 to Boyle, et al. issued Feb. 1, 2005 entitled “Digital video recorder employing a file system encrypted using a pseudo-random sequence generated from a unique ID”, U.S. Pat. No. 6,853,731 to Boyle, et al. issued Feb. 8, 2005 entitled “Digital video recorder employing a unique ID to interlock with encrypted video programs stored on a storage device”, United States Patent Publication No. 20020104019 to Chatani, et al. published Aug. 1, 2002 entitled “Method and system for securely distributing computer software products”, United States Patent Publication No. 20030049021 to Kamieniecki, published Mar. 13, 2003 and entitled “Apparatus for monitoring of DVD/CD usage and targeted DVD/CD sales utilizing a set top with DVD/CD capability”, and United States Patent Application No. 20040255139 to Giobbi published Dec. 16, 2004 entitled “Digital content security system”.
Other well-known approaches to digital rights and copyright management exist in the prior art. For example, several commercially available digital watermarking approaches including Digimarc®, SysCoP™, EIKONAmark™ can be used to embed steganographic data within the recorded or streamed content. Media rights management systems such as the Microsoft Windows® Media Digital Rights Manager (DRM), and the newer Windows Media Player 9, may be used as well.
However, despite the variety of different prior art techniques for providing content playback security in a digital video recording system, none address the particular issue of determining whether content selected for playback was obtained from the same network to which the playback device is currently connected. Accordingly, improved methods and apparatus for enforcing a network operator's content security, and associated business rules, are needed. Such improved methods and apparatus would ideally be implemented with only minimal modifications to the extant infrastructure and prevailing CPE software architectures, thereby allowing for ready implementation and backward compatibility in existing network applications.